Why do children get urinary tract infections?

Children's physical resistance is far less than that of adults. Not only common minor illnesses such as colds and fevers, but many adult diseases can also occur in children, such as the common urinary tract infections. Children are not aware of their own hygiene, and their hygiene is mainly taken care of by their family members. Urinary tract infections are most common in infants and young children. Why are children more prone to urinary tract infections?

Urinary tract infection (UTI), also known as urine infection, refers to the invasion of pathogenic microorganisms into the urinary system, reproduction in the urine, invasion of the urinary tract mucosa or tissue, and causing an inflammatory response. It is divided into upper urinary tract infection and lower urinary tract infection. The former refers to pyelonephritis, and the latter refers to cystitis and urethritis. Upper urinary tract infection is very harmful, with the highest incidence in infants and young children. Repeated infection can cause renal scarring, and in severe cases can lead to secondary hypertension and chronic renal failure.

Various pathogenic microorganisms are the causes of urinary infections, with Escherichia coli accounting for 75% to 90%, followed by Klebsiella pneumoniae, Proteus, Clostridium difficile and Bacillus subtilis. In recent years, the proportion of Gram-positive cocci has increased, such as Streptococcus aureus and Staphylococcus aureus. The bacteria that induce urine infection caused by instrument operation may be intestinal bacteria and Pseudomonas aeruginosa. Urinary infection complicated by urinary tract obstruction, structural abnormalities, urinary tract stones, vesicoureteral reflux and neurogenic bladder may be a mixed infection of more than one bacteria. Viral infections, particularly adenoviruses, can cause hemorrhagic cystitis. Fungal infections may occur secondary to indwelling catheterization in diabetes, immunodeficiency disorders, or during treatment with steroids, broad-spectrum antibiotics, or other immunosuppressants.

There are three main manifestations, depending on age and location of urine infection: pyelonephritis, cystitis and asymptomatic bacteriuria.

1. Pyelonephritis is mostly seen in infants and young children, with systemic infection and poisoning symptoms as the main manifestations, often with a fever above 38.5°C. When the fever is high, there may be convulsions or chills. At the same time, there are also general discomfort, listlessness, pale complexion, vomiting, nausea, and mild diarrhea. Older children complain of pain in the ribs or lower back, and percussion pain in the kidney area. Neonatal manifestations include sepsis, weight loss, feeding difficulties, jaundice, irritability, and fever or lack of temperature.

2. Cystitis mostly occurs in older girls, with symptoms of frequent urination, urgency, difficulty urinating, incomplete urination, lower abdominal discomfort, pain in the suprapubic area, urinary incontinence, sometimes foul-smelling urine, and vulvar eczema. Cystitis does not usually cause fever.

3. Asymptomatic bacteriuria Asymptomatic bacteriuria refers to a positive urine culture in children without any clinical symptoms of infection. Almost all of them are girls, but if untreated they may develop into symptomatic urinary tract infections.